Abstract
Decelerations frequently occur during sport and are often associated with non-contact knee injury mechanisms. Though decelerations place a high eccentric demand on the quadriceps, little is known about the relationship between quadriceps function and deceleration performance. Traditional functional testing batteries often over-estimate quadriceps function and lack assessments of deceleration performance, while current deceleration testing is often heavily reliant on technology and performed at shallow angles. The purpose of this clinical commentary is to describe the relationship between deceleration and quadriceps function, suggest two clinical tests to assess deceleration performance, and provide exercise suggestions for improving deceleration performance. The authors believe that assessing a deceleration task and a single leg retro hop may be a viable alternative for assessing the quadriceps when isokinetic or isometric testing may not be available. Level of Evidence: 5.